1. Field of the Invention
The present invention relates to an antithrombogenic material having a reduced stickiness to blood platelet, and a method for producing the antithrombogenic material.
2. Prior Art
In recent years, there has been a positive tendency that cell-embedded type hybrid artificial organs are applied to organs such as cutis, mucosa, blood vessel, liver, spleen or the like, whose functions cannot be sufficiently attained only by using substitute products made of an artificial material. Also, the development of biosensors, switching devices, bioreactors or the like, which utilize cells, have increasingly proceeded.
In the development of these devices, it has been an important task to select and design a matrix material serving as a support for cells to be cultivated. For instance, if blood platelet is adhered on a surface of the matrix material and thrombus is formed by the coagulation thereof, it becomes impossible to apply the matrix material to the aforementioned artificial organs, especially artificial blood vessel. That is, in the case where the matrix material is used to produce artificial organs or the like, it is inevitably required to control its stickiness to blood platelet in order to realize artificial organs having a high performance.
As conventional materials having a reduced stickiness to the blood platelet (hereinafter referred to as an "antithrombogenic material"), a polymer material to which heparin is bonded, a polymer material on which urokinase is fixed, a block copolymer of hydroxyethyl methacrylate with styrene or the like are exemplified. However, these polymer materials as antithrombogenic materials serve for reducing stickiness not only to the blood platelet but also to cells.
As described above, since the above-mentioned conventional antithrombogenic materials have reduced stickiness to both blood platelet and cells, it has been difficult to apply these materials to cell-embedded-type hybrid artificial organs due to poor adhesion to cells.
On the other hand, conventionally, as materials having reduced stickiness to blood platelet while maintaining stickiness to cells, there are known those produced by chemically modifying biopolymer proteins such as collagen. Specifically, Japanese Patent Application Laid-open No. Sho-58-165854 discloses a method in which blood compatibility of collagen and pseudo-formation of intima thereby are improved by succinylating amino groups (--NH.sub.2) as side chains in polypeptide chain of collagen.
In the method disclosed in the Japanese Patent Application, the biopolymer material having stickiness to cells is chemically inhibited from exhibiting stickiness to blood platelet.
The material described in the afore-mentioned Japanese Patent Application Laid-open No. Sho58-165854 is prepared by chemically modifying the amino groups as side chains in the polypeptide chain. However, since the chemical reaction for the chemical modification of the amino groups is difficult to control, the biopolymer material cannot be uniformly subjected to the chemical modification. For this reason, conventional antithrombogenic materials are not satisfactory in anti-thrombogenic property and stickiness to cells. Accordingly, there arises a problem that the conventional antithrombogenic materials have only a low reliability with respect to the anti-thrombogenic property and the stickiness to cells.
Further, the method disclosed in the afore-mentioned Japanese Patent Application Laid-open No. Sho58-165854 is associated with poor controllability of the chemical reaction in which the amino groups in the polypeptide chain are chemically modified, and complicated manufacturing processes. This leads to the difficulty in producing antithrombogenic materials having uniform anti-thrombogenic property and stickiness to cells.
The present invention has been accomplished in view of the afore-mentioned problems encountered in the prior art.